Material treating apparatus



Feb- 15 1955 L. J. FULLER MATERIAL TREATING APPARATUS 6 Shets-Sheet 1Original Filed May 15, 1945 r. E U WF J e m m a L Feb. 15, 1955 L. .1.FULLER MATERIAL TREATING APPARATUS 6 Sheets-Sheet 2 Original Filed May15, 1945 ffy. 5

INVENTOR. Lawrence J Fu ller Feb. 15, 1955 L J. FULLER MATERIAL TREATINGAPPARATUS Original Filed May l5, 1945 6 Sheets-Sheet 5 .E ma

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3 n@ E h www Swim o X.. uw um .wb s K INVENTOR. Lawrence J Fuller Feb.15, 1955 .1. FULLER Re- 23,948

MATRIAL TREATING APPARATUS Original Filed May 15, 1945 6 Sheets-Sheet 4r .ww .ww n e .J NQ @E o: N2 m2 E NQ E# f vi if n V\ N A f H ww L d e?QE NS v2 @E NS QN .MNM @S WS DE Q2, mm o:

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w, hb `||L| ||||||m n2 u N\\ N1 M JNN\ N\ \\-\1\ .SN E DI 2N wm Feb. 15,1955 L. J. FULLER MATERIAL TREATING APPARATUS Original Filed May 15,1945 /zos 6 Sheets-Sheet 5 Lawrence J Fuller BY Feb. 15, 1955 L. .1.FULLER MATERIAL TREATING APPARATUS Original Filed May 15, 1945 6Sheets-Sheet 6 Nw xm. LS N wmv United States Patent O MATERIAL TREATIN GAPPARATUS Lawrence I. Fuller, Norristown, Pa., signor to WeldingEngineers, Inc., Norristown, Pa., a corporation of Delaware Original No.2,615,199, dated October 28, 1952, Serial No. 593,928, May 18, 1945.Application for reissue May 20, 1953, Serial No. 356,329

26 Claims. (Cl. l8-12) Matter enclosed ln heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

rial will appear from the following specification taken in connectionwith the accompanying drawings in which Fig. 1 is a vertical sectionalview of a typical apparatus illustrating the treatment in accordancewith this invention, the section of the casing being taken on line 1-1of Fig. 2 and the worm along line 1-1 of Fig. 2 being shown in full;

Fig. 2 is a top plan view of the worm with [parts] the casing in sectionon the line 2--2 of Fig. l along a horizontal plane through the axis ofthe worms; t

Fig. 3 is a cross section taken on line 3-3 of Fig. .1;

Figs. 4 and 5 are front and side views respectively in elevation of amodified detail;

Fig. 6 is a side view, with parts broken away of a modification;

Fig. 7 is a plan view of the apparatus [shown in] taken along lines 7-7of Fig. 6 with top parts removed;

Fig. 8 is a side view, with parts broken away, of a furthermodification;

Fig. 9 is a side view, with parts broken away, of a furthermodification;

Fig. 10 is a [horizontal sectional view taken on line 10-10 of Fig. 8]top plan view of the worms shown in the embodiment of Fig. 8 with thecasing in section through a horizontal plane through the axis of theworms;

Fig. l1 is a side view of a top transfer block of the apparatus shown inFigs. 8 and 10;

Fig. 12 is a face view of the block shown in Fig. ll;

Fig. 13 is a section on line 13-13 of Fig. ll;

Fig. 14 is a side view of a bottom transfer block of the apparatus shownin Figs. 9 and 10;

Fig. 15 is a face view of said block;

Fig. 16 is a section taken on line 16-16 ot' Fig. I14;

Fig. 17 and 19 are partial sections showing in plan view modifiedfeeding and treating mechanism; and

Figs. 18 and 20 are vertical sectional views of the mechnnisnis of Figs.17 and 19 respectively.

ln the apparatus of Figs. l to 3 a double barrel 16, 17 is formedpreferably of welded plates and is provided with liners 18, 19 meetingat 20 (Fig. 3) and leaving a. slot 21 between the barrels. Feed worms22, 23 with opposite pitches to their flights are positioned in barrels16, 17 re spectively and are connected to be driven with oppositerotations so that their peripheries move downwardly to gether at thecenter (Fig. 3). e

Surrounding barrels 16, 17 are jackets 25, 26 for heatJ ing or coolingfluids, the jackets being divided into sections to control independentlythe temperatures of successive portions of the worm feed.

A hopper 27 has a bottom opening 28 feeding material down into thereceivin ends of the first fli ts 29, of the feed worms 22, 3. Theseflights 29, 0 are right Re. 23,948 Reissued Feb. 15, 1955 5 sections 31,32 to which the material is delivered by the forward flights 29, 30. Theparallel substantially adjacent worms 22, 23 thus carry the materialforward and force it into the reverse flights 31, 32 which in turn exerta retarding action on the forward movement of the material. The stems 31a, 32a of the flights 31, 32 respectively have a larger diameter thanthe stems 29a, 30a of 'the main extruder flights 29, 30 so that thecross-sectional area of the spaces 31b, 32b between the surfaces 31e,32e of the stems 31a, 32a and the adjacent cylinder wall surface 19a andcover surface 35 is substantially smaller than the cross-sectional areaof the spaces 29b, 30b between the surfaces 29C, 30e of the stems 29a,30a and the cylinder walls. This reduction in the space between thewalls impedes or retards the forward movement of the material. The firstresult of these retarding influences is to squeeze out fluids, ifpresent, which move from the high pressure areas in the reverse flightsection (Fig. l) to lower pressure areas atthe right, clearances beingprovided for this back flow. Liquids are drained oli' around the screwplugs 33 provided on the worms 22, 23 at the entrances to the barrels,clearances being allowed between the screw plugs and barrel liners forthis purpose, and gases pass out through the hopper or other openings.

A further important eirect of the action of the forward flights 29, 30forcing material into and through reverse flights 31, 32 is thegenerating of heat within the material itself due to the working actionof the worms creating internal friction within the material. There is noescape for the material except through the reverse flights so that theback pressure applied to the material and the heat developed by theinternal friction simultaneously act on the material as it is being fed,working the material thoroughly under pressure and internally generatedheat.

it is thus very completely mixed and conditioned for extrusion and forrelease of volatiles if any. This heated material plasticized orthoroughly mixed is released by predetermined regulation of the lengthof the reverse flights in which the material is confined and byproviding for release of the material from these reverse flights 31, 32any desired degree of working and heating may be attained. The escapingmaterial is either exposed to the atmosphere or a chamber suitablysupplied with inert gas or partial vacuum.

'l he regulation of these effects is attained by varying the length ofthe cover surface 35 confining the material in the reverse flights,longer covers building up more back pressure and causing generation ofmore heat. y

To accomplish this the opening 36 of the barrels 16, 17 is provided witha primary pressure cover 37 removably bolted in place and carrying areplaceable liner 38 held in place by retainer block 39. The undersurfaces ot' the cover block and liner are shaped to fit between theperipheries of the flights (Fig. 3). At this point the material emergesfrom the confined portions of the reverse flights 31, 32 into an opensection of the barrels constituting the release chamber 44 within casing45.

Through this release chamber 44 the feed is preferably slow, carryingthe hot treated material forward by the forward feed flights 46, 47 ofworms 22, 23, kneading it and constantly exposing new surfaces for therelease of volatiles, and delivering the material to the auxiliaryflight 48 and main discharge flight 49 running in the outlet ends ofbarrels 16, 17. These discharge flights are at much faster pitch and thebarrel 16 terminating short at the end wall 50 causes the material oi'auxiliary flight 48 to transfer laterally over to main extruder flight49 delivering the material through the screen 5l to the extruder die 52forming the flow into any desired cross sectional shape, such as a flatribbon strip.

The open section of the barrels at the relief chamber 44 may be atatmospheric or any desired pressure or partial vacuum, volatile gasesbeing removed according to conditions as provided. Additions of solid orfluid ingredients may be made here or in the hopper 27 for intermixtureinto the material being handled.

The forcing of the material through the reverse flights 31, 32 subjectsthe material to a concentrated squeezing and mixing, and simultaneouslydevelops heat within the individual particles. No part of the mass canescape this stage and all parts are treated in identically the samemanner and each increment of the feed is brought up to the desiredtemperature within a very short interval of time amounting usually to amatter of seconds. For instance, with some rubbery material containingmoisture, a larger part of which is removed in the first stage bydraining back from initial flights 29, 30, the remain- -ing moisture isvaporized off in the relief chamber 4-1 by the heat developed by theinternal friction in the previousl stages. This relief vaporizationterminates the rise in temperature and may somewhat lower thetemperature depending on the amount and type of the volatiles involvedand the pressure prevailing in the chamber 44.

The amount of working of the material and the rise in temperature may beregulated by the pitch and length of the reverse flights 31, 32. Asshown, these have a relatively steep pitch for slow back feed and forany given reverse flights the treatment of the material may becontrolled by varying the effective length of cover surface 35. Forinstance, the pressure control liner 38 may be replaced by one which isshorter or longer correspondingly reducing or lengthening the reversefeed and similarly reducing or increasing the amount of working andinternal friction and generation of heat.

Regulation of the temperature of the barrels at various stages may beaccomplished by dividing jacket 25 into sections. For instance, sections53, 54, 55, 56, 57 and 58 may have their temperatures controlledindependently of each other to obtain the most desired results by havingthe temperature of the barrel higher or lower than or the same as thetemperature of the material. The jacket 56 corresponding to the reliefchamber 44 will usually maintain heat in the material to aid in thevaporization, and similarly the remaining jackets 57 and 58 willmaintain the heated condition of the material for screening and formingby extrusion. These temperatures may be varied as desired to give a veryaccurate control of the condition of the material throughout the entireprocessing. The primary pressure cover 37 is removable for access to thereverse feed flights so that these may be inspected and thoroughlycleaned between runs.

The working of the material is widely variable to suit differentcompositions, and the stages of liquid and gas relief are usuallyseparate and independently controlled. It has been found particularlyadvantageous to create the high temperature quickly and within thematerial itself by internal friction following this with a prompt andsharp pressure release. In this way, the interval during which thematerial is under this high temperature is very short, amounting to onlya few seconds in some cases, and the following temperatures are alsoaccurately regulated. The processing may be applied to a wide variety ofingredients for purposes of mixing and/or plasticizing as well as forthe extraction of fluids. The material being handled may also be of thethermosetting type utilizing accurate control of heat to thoroughlyhomogenize the composition and employing heat generated at the reverseflights to initiate a partial chemical reaction causing a delayedthermosetting, conditioning the material for extrusion and subsequentcompletion of the thermosetting action.

Usually the thermosetting plastics would be introduced into the hopperas a mixture of powder constituents comprising the material to beextruded. The action of the feed worms plasticizes these ingredients andraises the temperature to a desired degree for extrusion under pressurethrough the forming die. The lapse of time from the heating step to theforming step would be only a matter of less than one minute, and mightbe of the order of ten to twenty seconds, so that the chemical actiontaking place during the treatment within the working material-would notbe sufficient to cause any objectionable or obstructive stiffening,particularly since the temperature of the material is under accuratecontrol and the high heat generated at the reverse flights is onlymaintained for a very limited duration. As a consequence, the hardeningand setting of the plastic would follow the extrusion, and the amount ofchemical action within the apparatus is carefully and preciselycontrolled.

In many cases it would be preferable to pass the extruded materialdirectly from the exfruding die to a heated zone to complete thethermosetting action to a desired degree. An example of this would be athermoplastic material becoming rigid when raised above itspolymerization temperature, the material being treated and extruded at atemperature just below this polymerization, after which the elevation ofthe temperature would complete the setting action. In some polymerizingmaterials the chemical action takes place over a sufficient period oftime so that the initial temperature for plasticizing and extruding willbe high enough to bring about the polymerization or thermosettingwithout additional heating subsequent to extrusion. Some material may beextruded in such form as to be transferred directly to pressing andmolding operations for forming and final thermosetting, hardening orcuring.

Temporary solvents or chemical agents, such as catalysis, may be addedto the original mix as aids in bringing about desired plasticizing orother effects, and then after serving these purposes these plasticizingor other agents may be squeezed out or driven off at the relief chamber44 beyond the reverse flight or in the double squeeze area, the materialbeing then advanced through the equipment and extruded as desired.

With rubber stocks the apparatus is especially effective in elevatingthe temperature by rapid mechanical working. The crude unvulcanizedstock either has its vulcanizng agent mixed in it or added in the hopper27. The stock vulcanizing agents and other ingredients are then workedup to temperature and extruded immediately into its desired nal form,such as tubing, dprovision being made, if required, to maintain theforme stock at the proper temperatures to complete the vulcanizationoperation.

Various modifications of the apparatus will be made to conform to therequirements of particular materials and treatments. The characteristiccontrol of the processing is the development of predeterminedtemperatures within the material during the rapid mechanical workmg andextruding operations.

The regulation of the counter flow action and consequent internalfrictional effects may be attained by adjustment of a movable section ofthe barrels over the reverse flights 31, 32. Figs. 4 and 5 show analternate method of control which can be installed in place of parts 37,S8-and 39 (Fig. 1). The cover block that forms the adjustable section ofthe barrels may be divided into relatively slidable parts 6l), 61 alongvertical plane 62. The rear stationary portion is removably bolted inplace and carries the adjustable portion 61 having its lower surfaces 63contoured to fit over the reverse flights 31, 32 with the centralportion cut away at 65 on the discharge end. The lower surfaces 63,forming passageways or spaces 31 b, 3217 with the surfaces 3Ic, 32e ofthe stems 31a, 32a. Screw bolt 66 attached to adjustable part 61, thatcan be raised or lowered by turning it, is threaded in bracket 68 andmay be locked in position with lock nut 67 so that the effectiveness ofthe reverse flights may be regulated. The indicating dial 64 for screw66 may be calibrated in any desired manner to show the various settingsof the adjustable block 61 which may be adjusted to various settingsduring the running of the material through the equipment.

Various modifications of the system may be resorted to involving specialhandling of the material. For instance, in Figs. 6 and 7 the worms 71,72 in jacketed barrels 73, 74 have entrance flights 75, 76 leading toreverse flights 77, 78 over which in space 79 is mounted the adjustablecover block 80 provided with the transfer passage 81 with relief opening82 at the upper portions of the reverse flights. This passage 81 extendsat an angle to the discharge orifice 83 leading to the entrance en offeed flight 84 of worm 71 A screen or die 85 may be interposed acrossthe orifice 83 forming the discharge into separate outflows. Thematerial fed to flight 84 meets the reverse flight 86 and is by-passedto ight 87 of worm 72. A central longitudinal partition 88 intervenesbetween the flights of worms 71 and 72 at their portions beyond reverseflights 77, 78. This partition may be perforated between flights 84, 86on one side and flight 87 on the other, and this confines the progressof the material through flights 84 and 86 in series subjecting thematerial to another pressure and temperature rise duc to the opposingactions of these forward and reverse feeds. 0r i1' such further workingis not'. desired, partition 8E may have a slot or openings permittingmaterial to pass laterally from flight 84 and 86 to flight 87. Suchmaterial meets with the resistance developed by reverse flight 89 and isby-passed back through orifices 90 in partition 88 to feed flight 91from which it is again passed back to the other side to flight 92, thecounter pressure for this final bypass being furnished by reverse flight93.

In this way there are a series of workings of the material back andforth against reverse flight resistance forcing the material throughorifices between stages in a manner giving it a very thorough mixing andmanipulation. Outlets for relief of fluids may be provided at anydesired points on the low pressure sides of the reverse screws asindicated at 94 and 95 and the final extrusion from feed screw 92 maypass the material through screens and dies as desired. At the entranceend the worms 71, 72 are provided with the plugs or hubs 96, 97retaining the material within the barrels while permitting escape ofliquid expressed under action of the opposed flights of the rst stages.

In Figs. 8 to l5 the feed worms 100, 101 in barrels 106, 107 haveflights 102, 103 at entrance leading to reverse flights 104, 105provided with either an upper or lower transfer block 108 or 109 havinga by-pass leading to the parallel feed flights 110, 111. The materialby-passed to flight 110 meets with the resistance of reverse flight 112and transfers over to the extrusion flight 111. As material passes downflight 111 fluids escape through openings 98 and run out relief opening99, any material passing through openings 98 is carried back by flight117 and is passed across to flight 111, discharging the material throughdie 113. Worms 1.00, 101 are provided with plug members 114, 115 at theopen ends of barrels 106, 107 leaving clearances 116 for backwarddischarge of liquids.

Upper by-pass block 108 is shown more in detail in Figs. 11, 12 and 13wherein the cover body block 118 has shoulders 119 resting on blocks 120(Fig. 8) and cover liner 121 held to the under surface of body 118 byscrews 122. The liner 121 has its under surface 123 fitted to theperipheries of the reverse flights 104, 105 and the entrance ends offeed flights 110, 111. At the reverse flight end the liner has entranceorifice 124 of a by-pass 127 formed by passage 125 of the liner incooperation with passage 126 in the under surface of body 118, thisby-pass 12 leading to discharge orifice 128 at the peripheries of thefeed flights 110, 111.

The lower by-pass block 109 is shown in Figs. 14, 15 and 16. Here thebody block 130 has shoulders 131 for bolting on blocks 132 (Fig. 9) andwith the upper surface 133 carrying liner plate 134 fastened by screws135. The upper surface 136 of plate 134 is shaped to t the peripheres ofthe reverse flights 104, 105 and feed flights 110, 111 and orifice 137and auxiliary orifice 138 lead to by-pass 139 formed by the matchingpassages 140, 141 in body 130 and plate 134 and branched at 142 indischarge orifices 143, 144 passing the material to the feed flights110, 111. Fluids released from high pressure areas escape throughopenings 145 when either top or bottom transfers shown in Figs. 8 and 9are used.

In Figs. 17 and 18 the feed worms 150, 151 in liner 152 of casing 153having jacket 154, carry the material to reverse flights 156, 157 underpressure block 158 from which the material discharges out into therelease space 162 above cylinders 159. At each end of these cylindersthe liner 152 is interrupted to provide spaces 160,' the ends of thecylinders overlapping slightly with the liner edges 161 to form bearingsurfaces. Rotation of the cylinders 159 carries the material aroundbetween them and often the mass being worked will tend to adhere to onecylinder or the other while progressing along toward the discharge 163under the pressure of the material accumulating behind it. The cylinders159 thus roll the material into sheet form as it passes through therelease space 162 providing extensive exposed surfaces for the escape ofvolatiles or the absorption of any added ingredients. The material fromdischarge at 162 is received by the feed flights 164 and passed on tothe extrusion openlng. l

In the modification shown in Figs. y,19 and 20 the pressure block 168carries the vertically movable section adjusted by screw 165 threaded inbracket 170 and swiveled 1n block 169. In this way by raising orlowering the block section 169 the back pressure may be varied on thematerial being worked by the forward and reverse flights 150, 151, 156,157. The worked material is passed mto the release chamber 182 above thefeed worms 167, 168 in the liners 172 and having the worm flightsstaggered as shown to grip the material along zig-zag lines and carry itaround between them and forward to the discharge 171 into the extrusionworms 173, 174. The cover 175 enclosing the chamber 182 has the outlet176 for release of volatiles under desired pressure or vacuum.

The flights of the feed screws may have their peripheries staggered asshown or running substantially in contact and the continuity of thehelicall peripheral portions may be interrupted if desired.

The treatment provided for by processing of this invention is widelyadaptable to a variety of materials, and the results obtainable arevaried. Materials are mixed, kneaded and worked under pressure releasingmechanically combined fluids. Heat is developed by friction within thematerial as the result of this working under pressure, the material maybe plasticized and volatiles may be distilled off as desired.

The material is then again subjected to pressure for straining andforming into shape. For instance, the process of manufacture ofsynthetic rubber is carried on in its finishing stages by starting witha slurry of water and soft masses or curds of granules of syntheticmaterial, the water being of the order of 300% on the dry basis forexample. The liquids are squeezed from the solids and drained off fromthe low pressure areas as the solids are advanced to a high pressurearea developed by the counter flow action. Heat is developed and thematerial becomes plasticized due to its intensive working underpressure. Then upon release into a low pressure zone the hot materialvolatilizes olf its moisture content, the resulting product having amoisture content of less than one half of one per cent. The hot driedmaterial is then put under pressure and forced through a strainer andformed into a ribbon or narrow sheet.

Materials with large amounts of entrapped gases and large quantities ofvolatiles, such as encountered in the finishing operation of polybutene,may be processed in the same manner. High pressures are developedsqueezing out the entrapped gas which is tapped off in the low pressureentrance zone where the material is fed in. Heat is developed byintensive working of the material under pressure causing it to becomeconglomerated. The heated material is then advanced to a low pressuresection where volatile substances, such as catalysts, are driven off.The hot treated material is then advanced under pressure developed forstraining and forming the mass into ribbons or narrow sheets.

Similarly wire coating thermoplastic compounds, such as those of theVinylite type, are either fed to the equipment in the form ofplasticized chips or tape. or a mixture of filler materials and plasticresin. With the ngredients in the form of powder, the compound isplasticized by the working under heat and pressure. The hot compound isthen advanced through the low pressure areas for the release of gasesand the driving off of any other volatiles. The conditioned hot com oundis then again put under pressure, forced throug a straining screen andthen extruded as a coating on the wire.

Some materials, such as phonograph record compounds, com-posed of resinsand fillers and in some cases substantially pure resins, are handled bythe same procedure. The raw material is introduced in the form ofplasticized chips or a mixture of powders composed of fillers andplastic resins. Where powder is used the compound is plasticized byworking it under heat and pressure, and it is then advanced through thelow pressure area for expulsion of the gases and volatiles and theconditioned hot compound is then extruded or fed directly to the diskforming die and then, preferably while still hot, is fed to the presswhere the finished record is pressed out on dies containing therecording impressions. The whole process can be accomplished in aslittle as from one to three minutes except in special cases where extraoperations are involved.

Forming of shapes and tubing by this process is attained by feeding,either plasticized or unplasticized, materialwhich is quickly raised intemperature by the working and kneading in the high pressure area andthe release of the gases and volatiles in the sudden expansion into thelow pressure area. The still hot processed material in the next pressurestep may be strained if desired and is formed through a suitable dieinto predetermined cross sectional shape.

These treatments are typical of the adaptability of the processing tocombine a heating, pressing and working of the material under controlledconditions giving a very thorough plasticizing action combined with adewatering and degasing and a swift development of the heat within thematerial itself. Then upon release of the hot plasticized material intoa region of lower pressure, the volatiles will vaporize off dependingupon the conditions maintained in the released chamber. The material maybe directly discharged from this release or as shown may be furtherworked and fed under pressure to straining and extruding a paratus asdesired. Also s-lugs may be formed of this eated and treated materialfor forming by hot presses injection moldin compression molding,transfer molding and cold mol ing. The succession of operations on thematerial has proved not only adaptable but highly efficient indispensing with separated steps and intermediate handling and hascontributed a speed of operation and a control of the time and timing ofthe heat and pressure hitherto unattainable.

l. In appara-tus for feeding and treating historial, a pair of paralleloppositely rotating worms, each `worm having a forward feeding flightand a reduced rate reverse feed tlight, barrel casings completelysurrounding said forward and reverse flights and retaining said materialin said forward and reverse flights under pressure yfor a predetermineddistance througl'i said reverse flights and provided with a releaseorifice in the casing ieading from the feed through said reverse flightsto a subsequent area of reduced pressure permitting discharge of saidmaterial from said reverse flights into said area only after saidpredetermined distance of travel of said lii'iaterial through saidforward and reverse flights.

2. Apparatus for feeding and treating material as set forth in claim 1iii which .the forward and reverse feed flights are interrupted in thecontinuity of their iieiical peripheral portions.

3. Apparatus for treating material comprising a. piu rality of parallel,sideby-side forward feeding rotary members of helical shape cooperatingto feed material, a plurality of obstructing rotary members at thedischarge ends of said feeding members imposing 'a countenactionopposite to said forward feed and developing heat and pressure ibykneading and working of the material at the area of said counter-actionand permitting passing of material under the action of said forward feedso as to de termine the rate of `feed through all of said members,encasing means surrounding and closely fitting the peripheries of saidrotary members to maintain the material under pressure during feedingand a restricted opening in said encasing means positioned to providedischarge means from said obstructing rotary members releasing thematerial into an area of reduced pressure.

4. Apparatus as set forth in claim 3 in which the discharge area ofreduced pressure is provided by a chamber containing mechanism rotatablelwith said rotary members and working the material .under predeterminedconditions of heat and pressure.

5. Apparatus as set forth in claim 3 iii which the discharge area ofreduced pressure contains mechanism rotatable with said rotary membersand working the material in surface contact with fluids excluding theatmosphere.

6. Apparatus as set forth in claim 3 in which mechanism rotatable withsaid rotary members and in the di-s cha-rge area of reduced pressureworks Ithe material to expose additional surface and feeds it forwardunder pressure to extrude it in desired form.

7. Apparatus as set forth in claim 3 in which the obstructing rotarymembers comprise reverse helical-screw formations of lower feed ratethan said forward feeding members and tending to feed the material in adirection opposite to the forward feed.

8. Apparatus as set 'forth in claim 3 in `which there is a surroundingjacketing in said casing means forming means' for controlling thetemperature 'of the .surfaces in contact with the material to regulateits temperature dur-- ing treatment.

9. Apparatus as set forth in claim 3 in which there are `outlets at theends of said rotary members forming clischarge means for tl-uid from the.materisi 'under presn sure in advance of said obstructing rotarymembers.

l0. kApparatus for treating material comprising a pair of parallelacting helically shaped members feeding the liti fili

said reverse feed means,

material forward, oppositely directed helically shaped 'members of lowerfeeding rate opposing the forward eed of said Vmaterial and permittingpassing of material through a predetermined extent of said reversemembers under the action of said forward feed, a casing meanssurrounding and closely fitting the peripheries of said helically shapedmembers to maintain pressure on the .material being treated and anoutwardly directed passage from said oppositely directed helicallyshaped members forming a discharge for said passed material into an areaof reduced pressure.

ll. Apparatus as set forth in claim l0 in `which the forward feedingpair of helically shaped members moves downward toward each other at thecenter and are supplied from a hopper above both of said members.

l2. Apparatus as set forth in claim 10 in which the position of thedischarge passage is adjustable -lengthwise of the oppositel directedmembers so that the length of the opposite y directed members opposingthe forward feed is variable `to regula-te the pressure and heatdeveloped.

13. A system for heating material comprising a pair ot opposltelythreaded and oppositely rotating feed screws subjecting the material torotary forward feeding 'from opposite sides, surrounding casing meansclosely fit-ting the periplieries of said feed screws to maintainpressure therein, a pair of oppositely threaded, oppositely rotatingreverse `feed screws ot' predetermined lower feed rate closely tted insaid surrounding casing vmeans and oounteractin said forward feed andthereby working the material un er pressure to develop a suddentemperature rise by friction in the material, the 'heated material'being forced a predetermined distance through said reverse feed, and a`discharge from said reverse feed Ireleasing the neared material outwardfrom said reverse feed into a space of lower pressure abruptly reducethe press-ure on the material.

ifi. A system for treating material as set forth in claim i3 .in whichthe forward feed screws have peripheral helices rutiii'iug at the samespeed and with the edge of one helix offset with respect to the edge ofthe other ln sta-ggered. relation and drawing in the material betweenthem.

l i5. A system for treating material as set forth in claim li in whichthere are parallel rotary members forming feeding means following thedischarge into the area of reduced pressure acting to work the materialto expose its surface.

16. .AA systei n t`or treating material to reduce its fluid contentcomprising means for forwardly feeding the maserial and a subsequentmeans applying a reverse feed effort on the material, said forward andreverse feed means putting the material under pressure within asurrounding easing to express liquid from said material, a drain fromsaid forward f eed for the discharge of said expressed liquid whilecontinuing said forward feed against and through and a discharge openingfor the material releasing said material from an intermediate point ofsaid reverse feed means into a region of lower pressure and permittingescape of gases from said discharged ma tarial in said lower pressureregion.

i7. A system for heating material as set forth in claim 416 iii whichthere is a pair of parallel forward feed screws receiving the materialfrom the reverse' feed, and a casing cooperating with said feed screwsto form an extrusion means working the discharged material and extrudingit after the extraction of gases therefrom.

18. A system for treating material to reduce its fluid contentcomprising a pair of forward feed screws and a hair of reverse screwscoaxial with said forward feed screws and feeding backward at a lowerrate to develop a gradient pressure on the material, a casingsurrounding and closely fitting the peripheries of said feed and reversescrews and cooperating therewith in expressing uids from said materialand producing high pressure and low pres sure areas, means ermittingfluids to flow from the high pressure areas to t e lower pressure areas,and discharge means drawing fluids from said low pressure areas.

i9. A system for treating material as set forth in claim iS haring thescrew feeds parallel and opposed and a casing enclosing them to confinethe material to kneading and working in the high pressure area togenerate heat by interrati friction, and n discharge from said reversefeed into a low pressure area, means in said low pressure areaworkingsaid material for the release of volatiles therefrom.

20. A system for treating plastic material comprising parallel actingrotary helices developing pressure on each side wnile radially retainingsaid material and constraining the material to torward4 longitudinalprogress, similar parallel acting rotary helices developing pressuresreversely directed and exerting a reverse reed action at a lower rate todevelop a corresponding counterpressure opposing said forward feed, saidforward feed acting to force the material through said reverse helicesagainst said connterpressure and simultaneously raising its temperature,and a discharge orice for said material releasing it from apredetermined point of said reverse feed so that said material is at arelatively high pressure at said point of release.

21. Apparatus for treating materialV comprising a plurality of parallel,side-by-side, helical, forward feeding, oppositely rotating rotarymembers cooperating to feed material, a plurality of obstructingoppositely rotating members at the discharge ends of said feedingmembers imposing a counterpressure opposite to said forward feed anddeveloping heat and pressure by kneading and working of the material atthe area of said counterpressure and permitting passing of materialunder the action of said forward feed so as to determine the rate offeed through all of said members, encasing means surrounding andenclosing the peripheries of said rotary members to maintain thematerial under pressure during feeding thereto, outlet means passing thematerial from said obstructing rotary members into an area of reducedpressure, and forward feeding means receiving said material in said areaand passing it under pressure to a second point of discharge.

22, Apparatus for treating material as set forth in claim 21 in whichthe area of reduced pressure is at a pressure below atmospheric.

23. In apparatus for feeding and treating material a pair of parallelbarrel casings side by side forming parallel cylindrical passages with acentral longitudinal opening between them, and oppositely rotating feedscrews having helical fights of similar opposite pitch, carrying thematerial through said passages and delivering it in parallel pathstherefrom with the peripheral edges of said ights in cylindricalcontours coaxial with said passages and substantially tangent at thecenter of said longitudinal opening, said ights being longitudinallystaggered with relation to each other so that the edges of the ightsalternate in sequence along said central longitudinal opening in allpositions of the feed screws.

24. An extruder comprising a cylinder having a feed opening at one endfor the introduction of material to be extruded from the other endthereof, a feed screw rotatable in said cylinder and adapted whenrotated to advance and t0 condition the material for extrusion, and flowcontrol means between the ends of said screw impeding free flow ofmaterial along said cylinder and screw and thereby building up a backpressure on the materialv in advance of said flow control means. saidflow control means comprising opposed surfaces on said screw and in saidcylinder defining a passageway therebetween of cross-sectional area lessthan that between adjacent portions of said screw and cylinder, saidfeed screw being formed with a rib along its` passageway definingsurface inducing counterflow of material for intimate mixing andblending of the material prior to and during flow through said flowcontrol means.

25. An extruder comprising a cylinder having a feed opening at one endfor the introduction of material to be extruded from the other endthereof, a feed screw rotatable t'n said cylinder and adapted whenrotated to advance and to condition the material for extrusion, flowcontrol means in the intermediate portion of said extruder providing apassageway which impedes free flow of material and thereby builds up aback pressure on the material in odvunee of said flow control means, andmeans for varying the flow aren of such passageway includingpassagewaydefining surfaces relatively movable closer to and furtherfrom each other whereby the flow area of such passageway may be variedto predeterminedly impede free flow of material therethrough inaccordance with the characteristics of the material being extruded.

26. An extruder according to claim 25 characterized further in that ventmeans are provided in the intermediate portion of said extrllderfollowing said flow control means for discharge of volatile ingredientsand trapped gas bubbles in the material prior to extrusion of thematerial from the other end of said cylinder.

References Cited in the le of this patent or the original patent UNITEDSTATES PATENTS 1,155,096 Price Oct. 12, 1915 1,364,549 Gordon Jan. 4,1921 1,849,291 Gordon Mar. 15, 1932 1,871,416 Broadeld Aug. 9, 19321,990,555 Loomis Feb. 12, 1935 2,119,162 Hartner May 31, 1938 2,146,532Crane et al. Feb. 7, 1939 2,175,054 Ferngren et al. Oct. 3, 19392.365,374 Bailey Dec. 19, 1944 2,431,274 Osborne Nov. 18, 1947

